1. Field of the Invention
The present invention relates to a still picture signal processing apparatus and, more specifically, it relates to a still picture signal processing apparatus for an electric still camera.
2. Description of the Prior Art
Recently, various electronic still camera systems have been proposed which convert the image of an object into electric signals by an image pickup device, record the same on a magnetic disc called a floppy disc and display a still reproduction image on a monitor TV. These electronic still camera systems are disclosed in
(1) Nikkei Electronics, July 2, 1984 pp. 80-85 PA0 (2) Aizawa, et al.: HIGH RESOLUTION ELECTRONIC STILL CAMERA WITH TWO MOS IMAGERS, IEEE transactions on Consumer Electronics, Vol. CE-13, No. 3, August 1985 pp. 425-429 PA0 (3) Tanaka, et al.: AN ELECTRONIC STILL CAMERA SYSTEM, IEEE Transactions on Consumer Electronics, Vol. CE-32, No. 3, Aug. 1986 pp. 345-353 PA0 (4) Kihara et al.: THE ELECTRONIC STILL CAMERA A NEW CONCEPT IN PHOTOGRAPHY, IEEE Transactions on Consumer Electronics Vol. CE-28, No. 3, August 1982 pp. 325-321
As disclosed in the above mentioned publications, in an electronic still camera, the luminance signal and the color difference line sequential signal are respectively FM modulated and frequency multiplied, whereby one field is recorded on one track. For a frame image, the recording is carried out on two adjacent tracks. However, both the field image and the frame image exist together on the same disc. The discrimination between the two is achieved by a 2 bit field/frame discriminating signal included in the DPSK modulation data code which is multiply recorded in the video signal (see the above publication (1)). The processing of the reproduction signal of the magnetic disc recorded by the above mentioned electronic still camera is carried out by a still picture signal processing apparatus provided in the reproduction apparatus. The still picture signal processing apparatus temporarily stores the video signal reproduced from the magnetic disc in a memory and repeatedly reads the stored content of the memory, thereby supplying the still picture signal to the monitor TV.
Meanwhile, in order to save the tracks on the magnetic disc, sometimes one of the two tracks, on which the frame recording is carried out, is erased and a new still picture image is recorded on that erased track. In this case, the relation of the field/frame discriminating signal may be mixed with each other between the remaining one track of the frame recording and the succeeding track of the new still picture image. Therefore, in a conventional still picture signal processing apparatus, there is a possibility of errors in reproducing such a magnetic disc. For example, the track of the frame recording which is not erased and the succeeding one track of the new still picture image are sometimes discriminated as a frame image and both are mixed and reproduced to be displayed on the monitor TV. In that case, still picture images completely independent of each other are mixed and displayed on the monitor TV. Therefore, the user watches a meaningless image, wondering whether the reproduction apparatus is out of order.